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Synthesis and reactions of 3‐carbethoxy and 3‐aroyl‐3,4‐dihydro‐1 h ‐2,3‐benzoxazin‐1‐ones
Author(s) -
Trani Aldo,
Bellasio Elvio
Publication year - 1977
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570140122
Subject(s) - chemistry , hydrazoic acid , benzoic acid , hydrazide , curtius rearrangement , hydrazine (antidepressant) , yield (engineering) , hydrolysis , medicinal chemistry , ethanol , nitrous acid , organic chemistry , metallurgy , materials science , chromatography
A series of 3‐substituted 3,4‐dihydro‐1 H ‐2,3‐benzoxazin‐1‐ones (IV) (Scheme I) was prepared by reaction of 2‐bromomethylbenzoyl chlorides (II) with N ‐hydroxyethylcarbamate (III) or with benzohydroxamic acids. Acid hydrolysis of 3‐carbethoxy (IVa) and 3‐benzoyl derivatives (IVb) afforded a mixture of 2‐(hydroxyaminomethyl)benzoic acid (V) and 2,3‐dihydro‐2‐hydroxy‐1 H ‐1‐isoindolinone (VII). Compound IVa reacted with ethanol, amines or hydrazine to yield the ethyl ester X, amides XIV (Scheme II) and the hydrazide XII of 2‐( N ‐carbethoxy‐ N ‐hydroxy‐aminomethyl)benzoic acid. Diazotization of the hydrazide XII afforded the unstable azide XIII which did not undergo the Curtius reaction but gave the benzoxazinone IVa by loss of hydrazoic acid.